Page 1 of 1
Nikon Abbe 1.25 condenser with loose front lens
Posted: Wed Aug 17, 2022 6:54 am
by karhukainen
It's starting to seem I can't buy any microscopy equipment that isn't in some way faulty. This time it's a condenser that I bought with a filter kit because the kit is incompatible with my current condenser (and because that condenser is also a bit broken). It arrived a bit dirty and when I finally got around to cleaning it, the front lens became loose. I contacted the seller and so forth but while waiting for a reply, I was hoping someone could tell me if it's easy to fix this (I would assume yes). I can't easily buy replacing equipment in my country, so I'd like to know what my options are.
Re: Nikon Abbe 1.25 condenser with loose front lens
Posted: Wed Aug 17, 2022 10:49 am
by apochronaut
Those are required to be leak free because that condenser is an oil immersion type. Usually the top lens is press fit into a relief and then furled, which is impossible to do at home.
If the correct alignment for it is evident, such as the relief being a snug f it a fine, thin line of epoxy run around the part of the plano surface that is concealed will seal it. aometimes a little will squeeze out and you have to remove it.
If the alignment is not evident, you could tack it with a tiny amount of putty then try it out and manually adjust it. Apply a thin line of epoxy between the back of the lens and it's surround once adjusted.
Be very careful not to allow any epoxy to ride up the side of the rear hemisphere. Just a thin line is all you need. I use a tiny screwdriver or a probe to run the line of cement and I do it under a stereo microscope but that isn't necessary.
The front lens will be somewhere around .90 N.A. , so even if the epoxy bead isn't evident when the lens is used dry, it might be when oiled and working at a more oblique angle, so be careful with the epoxy. You would be surprised how much of that back hemisphere is being used.
Re: Nikon Abbe 1.25 condenser with loose front lens
Posted: Thu Aug 18, 2022 5:26 am
by karhukainen
apochronaut wrote: ↑Wed Aug 17, 2022 10:49 am
Those are required to be leak free because that condenser is an oil immersion type. Usually the top lens is press fit into a relief and then furled, which is impossible to do at home.
If the correct alignment for it is evident, such as the relief being a snug f it a fine, thin line of epoxy run around the part of the plano surface that is concealed will seal it. aometimes a little will squeeze out and you have to remove it.
If the alignment is not evident, you could tack it with a tiny amount of putty then try it out and manually adjust it. Apply a thin line of epoxy between the back of the lens and it's surround once adjusted.
Be very careful not to allow any epoxy to ride up the side of the rear hemisphere. Just a thin line is all you need. I use a tiny screwdriver or a probe to run the line of cement and I do it under a stereo microscope but that isn't necessary.
The front lens will be somewhere around .90 N.A. , so even if the epoxy bead isn't evident when the lens is used dry, it might be when oiled and working at a more oblique angle, so be careful with the epoxy. You would be surprised how much of that back hemisphere is being used.
Thank you!